Dynamic loading for a switching power supply

ABSTRACT

A power supply unit provides power to a common output node. The power supply unit includes a first power conversion block electrically coupled to convert the electrical power input to a first output power supply share supplied to the common output node. The first power conversion block is configured to decrease output voltage from the first power conversion block based at least in part on output current from the first power conversion block reaching a rated current level. A second power conversion block is electrically coupled to convert the electrical power input to a second output power supply share supplied to the common output node. The second power conversion block is configured with a predesignated open circuit voltage setting and is further configured to contribute the second output power supply share to the common output node based at least in part on the output voltage at the common output node decreasing to the predesignated electrical voltage setting.

BACKGROUND

Electronic devices, such as computing devices, communication devices,and Internet-of-Things (IoT) devices, include one or more powersupplies. Furthermore, many electronic devices can operate at differentload scenarios. For example, in “awake” mode, an electronic device candemand a higher load from its power supply than in a “sleep” mode.

SUMMARY

The described technology provides a power supply unit for providingconverted power from an electrical power input to a common output node.The power supply unit includes a first power conversion blockelectrically coupled to convert the electrical power input to a firstoutput power supply share supplied to the common output node. The firstpower conversion block is configured to decrease output voltage from thefirst power conversion block based at least in part on output currentfrom the first power conversion block reaching a rated current level.The power supply unit also includes a second power conversion blockelectrically coupled to convert the electrical power input to a secondoutput power supply share supplied to the common output node. The secondpower conversion block is configured with a predesignated open circuitvoltage setting and is further configured to contribute the secondoutput power supply share to the common output node based at least inpart on the output voltage at the common output node decreasing to thepredesignated electrical voltage setting.

This summary is provided to introduce a selection of concepts in asimplified form that is further described below in the DetailedDescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Other implementations are also described and recited herein.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 illustrates an example electronic device powered with dynamicloading by a switching power supply.

FIG. 2 illustrates an example power supply unit (PSU) providing dynamicloading for a switching power supply with two power conversion blocks.

FIG. 3 illustrates example power supply operational characteristics attwo different loads with two power conversion blocks.

FIG. 4 illustrates a schematic of an example power supply unit (PSU)providing dynamic loading for a switching power supply with three powerconversion blocks.

FIG. 5 illustrates an example power supply unit (PSU) providing dynamicloading for a switching power supply with three power conversion blocks.

FIG. 6 illustrates example power supply operational characteristics atthree different loads with three power conversion blocks.

FIG. 7 illustrates example operations for dynamic loading for switchingpower supplies.

FIG. 8 illustrates exampled hardware and software that can be useful inimplementing the described technology.

DETAILED DESCRIPTIONS

Many power supplies are more efficient at different power loads. Forexample, a main power converter of a power supply unit (PSU) in anelectronic device may be less efficient at lower loads and moreefficient at higher loads, while an auxiliary or standby power convertermay be more efficient at lower loads and less efficient at higher loads.Furthermore, fast responses by a PSU to changes in power load can alsoprovide improved efficiency of the overall power supply. Use of digitallogic and load balancers to manage load changes in a PSU is expensiveand does not provide the desired rapid response and efficiency.Naturally, electronic device manufacturers wish to design their productswith the highest efficiency possible to reduce power consumption fromthe electrical grid, to extend the useful period on a single batterycharge, and to extend the useful lifetime of a battery. Nevertheless,optimizing power supply efficiency under different load conditions is achallenging engineering objective.

The described technology provides a system for dynamically coordinatingtwo or more power supplies at different load conditions. The systemincludes multiple power converters tuned to variable load conditions,such that the system sequences the power supplied by the different powerconversion blocks according to the substantially most efficientoperation.

FIG. 1 illustrates an example electronic device 100 powered with dynamicloading by a switching power supply. The electronic device 100 is shownin FIG. 1 as a laptop computer, but other electronic devices that demandvariable power loads may be powered by the described technology. Animplementation of the described technology may be implemented, forexample, within a power supply unit (such as a PSU 102), which receivesalternating current (AC) power from an electrical grid and converts itto direct current (DC) power for the electronic device 100. In otherimplementations, the PSU may reside within the electronic device 100.

Within the PSU 102, power supply circuitry includes multiple powerconversion blocks capable of contributing to supply power efficiently ata variable power load in the electronic device 100. The power load can,for example, vary between “sleep” power mode (a light load) and an“awake” power mode (a heavy load), between driving a single peripheral(e.g., a display) or multiple peripherals (e.g., displays, external harddrives). One type of power converter can be designed for best efficiencyat light loads, while another can be designed for best efficiency atheavy loads. As such, multiple power converters can be included in thePSU 102 to operate primarily in load conditions that correspond to eachpower converter’s best efficiency. Furthermore, the described technologyprovides a low-cost design (e.g., a design that does not requireexpensive load balancing logic or expensive enable logic that isresponsive to system standby signals) while providing a rapid transitionbetween different power converters to make the best use of each powerconverter’s most efficient operation. In some implementations,individual power conversion blocks can contribute their power supplyshares in aggregate to a common output node. In other implementations,an individual power conversion block can provide its power supply shareto the common output node, while one or more other power conversionblocks are excluded from providing their power supply share to thecommon output node. Note, however, that the one or more other powerconverters may still provide ancillary power contributions, such as tomaintain a charge on input capacitors.

The PSU 102 includes two or more power conversion blocks. In oneimplementation, the PSU 102 includes two power conversion blocks, onethat dominates the power supplied to a common output node (see output206) in light load conditions and another that dominates the powersupplied to the common output node in heavy load conditions. In otherimplementations, additional power conversion blocks may be included toaccommodate more granular load conditions. The contributions of eachpower conversion block are managed according to relative setpoints(e.g., predesignated open circuit voltage settings) of the outputvoltage. In this manner, the multiple power conversion blocks cancoordinate their power contributions to the common output node whilemaximizing or substantially maximizing the power conversion efficiencyof the PSU 102 with relying on expensive logic or external signalsprovided by the applications, operating system, or firmware of theelectronic device 100.

FIG. 2 illustrates an example power supply unit (PSU 200) providingdynamic loading for a switching power supply with two power conversionblocks. The PSU 200 receives AC power at an input 202 and converts itinto DC power, which it supplies to the common output node.

The PSU 200 includes a main power conversion block 208 and an auxiliarypower conversion block 210. The main power conversion block 208 hashigher power conversion efficiency at heavier loads than the auxiliarypower conversion block 210. The auxiliary power conversion block 210 isconfigured with a predesignated open circuit voltage setting (e.g., 12volts) and in an operational mode in which the output voltage at thecommon output node decreases as the output current from the auxiliarypower conversion block 210 reaches (e.g., increases to) a rated currentlevel. This operational mode may be accomplished, for example, bysetting the auxiliary power conversion block 210 to operating in aconstant current mode or a constant power mode, although otherimplementations may be employed. As such, as power supplied to thecommon output node increases (e.g., past a predesignated point), theoutput voltage at the common output node decreases (e.g., to maintainthe constant current to the common output node). It should be understoodthat the terms “constant current mode,” “constant power mode,” and“constant voltage mode” refer to the circuit configurations thatmaintain a substantially constant current/power/voltage in select rangesof operations, and that the levels of these parameters may vary slightlyfrom their respective set levels during operation in those selectranges.

In contrast, the main power conversion block 208 is configured with apredesignated open circuit voltage setting (e.g., 11 volts) that islower than the predesignated open circuit voltage setting of theauxiliary power conversion block 210. In one implementation, the mainpower conversion block 208 is configured to operating in a constantvoltage mode, although other implementations may be employed.Accordingly, at light loads (e.g., where the output voltage at thecommon output node is greater than the predesignated open circuitvoltage setting of the main power conversion block 208), the auxiliarypower conversion block 210 provides all or most of the output power tothe common output node. The main power conversion block 208 contributessubstantially no output power share to the common output node at such alight load. As the power supplied to the common output node increases toa point (a heavy load) where the output voltage at the common outputnode decreases to the predesignated open circuit voltage setting of themain power conversion block 208 (e.g., 11 volts), the main powerconversion block 208 is enabled to contribute to the output powersupplied to the common output node, supplying some or all of the outputpower, depending on the implementation.

In one implementation, the PSU 200 may include a controller 212, whichcan terminate the supply of output power by either of the powerconversion blocks. For example, if the auxiliary power conversion block210 has low efficiency in a portion of the heavy load range, thecontroller 212 can turn off the output power contribution of theauxiliary power conversion block 210 to the common output node in thatportion of the heavy load range. In this manner, the PSU 200 can rely onthe more efficient power conversion block in the corresponding portionof a load range and turn off the power output of the less efficientpower conversion block in that portion of the load range, therebyincreasing the aggregate power conversion efficiency of the PSU 200. Inone aspect, this allows the converters to work sequentially in theirrespective regions of highest efficiency in some implementations.

FIG. 3 illustrates example power supply operational characteristics 300under two different loads with two power conversion blocks. The y-axisrepresents output voltage at a common output node, and the x-axisrepresents output current to the common output node. An auxiliary powerconversion block is configured with a predesignated open circuit voltagesetting (e.g., a setpoint) of 12 volts, and a main power conversionblock is configured with a predesignated open circuit voltage setting of11 volts.

In a light load range, the auxiliary power conversion block suppliesoutput power to the common output node at a substantially constantoutput voltage, primarily or entirely to the exclusion of the main powerconversion block. However, as the power supplied to the common outputnode increases, the auxiliary power conversion block reaches a point atwhich its output current is constrained by the maximum rated current ofthe auxiliary power conversion block. That is, the power supplied to thecommon output node reaches a point at which the auxiliary powerconversion block cannot supply a higher output current, and thereforethe output voltage begins to decrease at a point 302 according to Ohm’sLaw. It should be understood, however, that the voltage/current curvemay follow a different type of curve (e.g., a different decreasing curveas one or more other power conversion blocks switch on).

At a point 304, the output voltage at the common output node hasdecreased to 11 volts (the predesignated open circuit voltage setting ofthe main power conversion block), which causes the main power conversionblock to begin to contribute a share of output power to the commonoutput node. In one implementation, the predesignated open circuitvoltage setting of the main power conversion block is set to a voltagethat will “turn on” the main power conversion block before the auxiliarypower conversion block is overloaded (at point 306).

In one implementation, the main power conversion block provides all ofthe power to the common output node in the heavy load range (e.g., powersupplied by the auxiliary power conversion block is terminated by acontroller that monitors the output current from the main powerconversion block). As the power load drops to a certain value, theauxiliary power conversion block can turn on again (and the main powerconversion block can turn off again) without overhead and powerdisruption to the electronic device. In an alternative implementation(e.g., at a power load level where the auxiliary power conversion blockis efficient), the auxiliary power conversion block can still contributea share of the total power supplied to the common output node.

An example scenario is provided below herein. Assuming the loadobjective is to draw 25 W, based on the load tables below. Because theauxiliary power conversion block maxes out at 20 W, then at a 25 W load,the power supply unit can be configured such that both converters cansupport the total load or only the main power conversion block cansupport the total load. From the efficiencies charts below, the totalefficiency is better if the design supplies power from the main powerconversion block in this state - the load is consolidated to the mainpower conversion block in its more efficient load condition. The overallefficiency of the power supply unit depends on the efficiency curves foreach power conversion block, so, if the load table parameters aredifferent, another implementation may achieve a more efficient loadcondition using both the main power conversion block and the auxiliarypower conversion block within a same portion of the load range.

Efficiency Per Converter: Aux Output Power Aux Converter Efficiency MainConverter Output Power Main Converter Efficiency 5 W 80% 5 W 50% 20 W90% 20 W 80% 25 W n/a 25 W 87%

Total Efficiency for 25W Load Scenario: 25W Load Scenario 1: Auxsupplies 20W Main supplies 5W 25W Load Scenario 2: Aux supplies 0W Mainsupplies 25W Output power (W) 25 25 Aux Input Power (W) 22.2 0.0 MainInput Power(W) 10.0 28.7 Total input Power Loss (W) 7.2 3.7 Efficiency78% 87%

FIG. 4 illustrates a schematic of an example power supply unit (PSU 400)providing dynamic loading for a switching power supply with two powerconversion blocks (a main power conversion block 402 and an auxiliarypower conversion block 404). The PSU 400 receives AC power at input 406and outputs DC power at output 408. The input 406 passes the AC powerthrough an electromagnetic interference filter 410 to an input rectifier412, which converts the AC power to a rectified signal. In animplementation (e.g., of a power supply united of greater than 75Watts), the rectified signal is passed through a power factor correction(PFC) circuit 414 to shape the input current in order to maximize thereal power from the AC power source. In other implementations, the PFCmay be omitted.

Input bulk capacitors 416 receive the rectified signal and smooths itfor input to the main power conversion block 402 and/or the auxiliarypower conversion block 404. In one implementation, the input bulkcapacitors 416 may all be connected to the input to the conversionblocks, or some or all of the input bulk capacitors 416 may bedistributed into conversion blocks themselves.

The schematic of FIG. 4 illustrates an example power supply unit inwhich the main power conversion block 402 is more efficient at powerconversion under heavy loads and the auxiliary power conversion block404 is more efficient at power conversion under lighter loads.Accordingly, in one or more embodiments, the PSU 400 is designed toallocate all or most of the power conversion in a light load range tothe auxiliary power conversion block 404 and all or most of the powerconversion in a heavy load range to the main power conversion block 402.Nevertheless, other designs may be employed. The “heavy” and “light”terminology is intended to provide a relative magnitude to the variableloads at different operation scenarios, and the extents of the heavy andlight load ranges are dependent upon the efficiency of the differentconversion blocks over the ranges. For example, an example main powerconversion block may suffer from lower efficiency as compared to theauxiliary power conversion block at some load up to 20 Watts. Likewise,the auxiliary power conversion block may be unable to supply power atloads greater than its maximum load rating of 20 Watts. It should beunderstood that the maximum loads, maximum currents, overload currents,and predesignated open circuit voltage settings of any conversion blockmay be designed to support defined operational characteristics for theelectronic device.

Because the main power conversion block 402 is less efficient at lighterpower loads, the auxiliary power conversion block 404 is set to a higherpredesignated open circuit voltage setting than the main powerconversion block 402 so that the auxiliary power conversion block 404turns on before the main power conversion block 402 at lighter powerloads. The “turn on” setpoint of each conversion block is controlled bythe predesignated open circuit voltage setting and is based on theoutput voltage at the common output node of each conversion block, whichis monitored by feedback controls in each conversion block (i.e., afeedback control 420 in the main power conversion block 402 and afeedback control 422 in the auxiliary power conversion block 404) - aconversion block turns on when the output voltage at the common outputnode drops below the corresponding predesignated open circuit voltagesetting.

In the auxiliary power conversion block 404, the feedback control 422monitors the output voltage at the common output node and controls theoperation of an auxiliary power converter 424 through a signal isolator426 (such as an opto-coupler). If the predesignated open circuit voltagesetting of the auxiliary power conversion block 404 is set to 12 voltsand the output voltage is 12 volts or lower, then the feedback control422 enables the auxiliary power converter 424 to supply power through anauxiliary transformer 428 and an auxiliary rectifier 430 to the commonoutput node.

Likewise, in the main power conversion block 402, the feedback control420 monitors the output voltage at the common output node and controlsthe operation of a main power converter 432 through a signal isolator434 (such as an opto-coupler). If the predesignated open circuit voltagesetting of the main power conversion block 402 is set to 11 volts andthe output voltage decreases to 11 volts, then the feedback control 420enables the main power converter 432 to supply power through a maintransformer 436 and a main rectifier 438 to the common output node.

As such, based on the relative predesignated open circuit voltagesettings of the individual conversion blocks, one or both conversionblocks may be supplying power to the common output node. In analternative implementation, a controller (not shown) may be used to turnoff one or the other conversion block in an effort to increase theoverall efficiency of the PSU 400 in certain load ranges.

Output bulk capacitors 440 receive the rectified signal(s) from one orboth of the conversion blocks and smooths the rectified signal(s) foroutput to the electronic device. In one implementation, the output bulkcapacitors 440 may all be connected to the outputs of both conversionblocks, or some or all of the output bulk capacitors 440 may bedistributed into conversion blocks themselves.

FIG. 5 illustrates an example power supply unit (PSU) 500 providingdynamic loading for a switching power supply with three power conversionblocks. The PSU 500 receives AC power at an input 502 and converts itinto DC power, which it supplies to a common output

The PSU 500 includes a main power conversion block 508, an auxiliarypower conversion block 510, and an auxiliary power conversion block 511.The main power conversion block 508 has higher power conversionefficiency at heavier loads than the auxiliary power conversion block510 and the auxiliary power conversion block 511. Likewise, theauxiliary power conversion block 510 has higher power conversionefficiency at heavier loads than the auxiliary power conversion block511. As can be seen in FIG. 6 , this configuration provides threedifferent load ranges in which one or more of the power conversionblocks are supplying power to the common output node.

The auxiliary power conversion block 510 is configured with apredesignated open circuit voltage setting (e.g., 12 volts) and in anoperational mode in which the output voltage at the common output nodedecreases as the output current from the auxiliary power conversionblock 510 reaches a rated current level. This operational mode may beaccomplished, for example, by setting the auxiliary power conversionblock 510 to operate in a constant current mode or a constant powermode, although other implementations may be employed. As such, as thepower at the common output node increases, the output voltage at thecommon output node decreases (e.g., to maintain the constant current orpower to the common output node). For example, in one or moreimplementations, each auxiliary power conversion block will reach itssubstantially maximum load capacity before the “next” power conversionblock begins to supply power, wherein “next” refers to the powerconversion block with the next lower predesignated open circuit voltagesetting. Other implementations may be employed wherein reaching thesubstantially maximum load capacity is not a prerequisite to turning onanother power conversion block.

In contrast, the auxiliary power conversion block 511 is configured witha predesignated open circuit voltage setting (e.g., 11.5 volts) and inan operational mode in which the output voltage at the common outputnode decreases as the output current from the auxiliary power conversionblock 511 reaches another rated current level. This operational mode maybe accomplished, for example, by setting the auxiliary power conversionblock 511 to operate in a constant current mode or a constant powermode, although other implementations may be employed. As such, as thepower at the common output node increases into the medium load range,the output voltage at the common output node decreases (e.g., tomaintain the constant current or power to the common output node).

It should be understood that more than two auxiliary power conversionblocks may be used to provide finer-grained control over powerconversion efficiency in additional subdivisions of the total electricalload range.

The main power conversion block 508 is configured with a predesignatedopen circuit voltage setting (e.g., 11 volts) that is lower than thepredesignated open circuit voltage setting of the auxiliary powerconversion block 510 and the auxiliary power conversion block 511. Inone implementation, the main power conversion block 508 is configured tooperating in a constant voltage mode, although other implementations maybe employed. Accordingly, at light loads (e.g., where the output voltageat the common output node is greater than the predesignated open circuitvoltage setting of the main power conversion block 508), one or both ofthe auxiliary power conversion blocks provide all or most of the outputpower to the common output node. The main power conversion block 508contributes substantially no output power to the common output node atsuch a light load. As the power at the common output node increases to apoint (a heavy load) where the output voltage at the common output nodedecreases to the predesignated open circuit voltage setting of the mainpower conversion block 508 (e.g., 11 volts), the main power conversionblock 508 contributes to the output power supplied to the common outputnode, supplying some or all of the output power, depending on theimplementation.

In one implementation, the PSU 500 may include a controller 512, whichcan terminate the supply of output power by any of the power conversionblocks. For example, if the auxiliary power conversion block 510 has lowefficiency in a portion of the medium load range, the controller 512 canturn off the output power contribution of the auxiliary power conversionblock 510 to the common output node in that portion of the medium loadrange. Likewise, if the auxiliary power conversion block 511 has lowefficiency in a portion of the heavy load range, the controller 512 canturn off the output power contribution of the auxiliary power conversionblock 511 to the common output node in that portion of the heavy loadrange. Similarly, the controller 512 can also turn off the powercontribution of the main power conversion block 508. In this manner, thePSU 500 can rely on the more efficient power conversion block or blocksin the corresponding portion of the load range and turn off the poweroutput of the less efficient power conversion block(s) in that portionof the load range, thereby increasing the aggregate power conversionefficiency of the PSU 500.

FIG. 6 illustrates example power supply operational characteristics 600under three different loads with three power conversion blocks. They-axis represents output voltage at a common output node, and the x-axisrepresents output current at the common output node. An auxiliary powerconversion block 1 is configured with a predesignated open circuitvoltage setting (e.g., a setpoint) of 12 volts, an auxiliary powerconversion block 2 is configured with a predesignated open circuitvoltage setting of 11.5 volts, and a main power conversion block isconfigured with a predesignated open circuit voltage setting of 11volts.

In a light load range, the auxiliary power conversion block suppliesoutput power to the common output node at a substantially constantoutput voltage, primarily or entirely to the exclusion of the main powerconversion block and the auxiliary power conversion block 2. However, asthe power load increases, the auxiliary power conversion block 1 reachesa point at which its output current is constrained by the maximum ratedcurrent of the auxiliary power conversion block 1. That is, the loadreaches a point at which the auxiliary power conversion block 1 cannotsupply a higher output current, and therefore the output voltage at thecommon output node begins to decrease at a point 602 according to Ohm’sLaw or another similar relationship.

At a point 604 in the medium load range, the output voltage at thevariable load has decreased to 11.5 volts (the predesignated opencircuit voltage setting of the auxiliary power conversion block 2),which causes the auxiliary power conversion block 2 to begin tocontribute a share of output power to the common output node. In oneimplementation, the predesignated open circuit voltage setting of themain power conversion block is set to a voltage that will “turn on” theauxiliary power conversion block 2 before the auxiliary power conversionblock 1 is overloaded.

At a point 606, the output voltage at the variable load has decreased to11 volts (the predesignated open circuit voltage setting of the mainpower conversion block), which causes the main power conversion block tobegin to contribute a share of output power to the common output node.In one implementation, the predesignated open circuit voltage setting ofthe main power conversion block is set to a voltage that will “turn on”the main power conversion block before the auxiliary power conversionblocks are overloaded.

In one implementation, the main power conversion block provides all ofthe power to the common output node in the heavy load range (e.g., powersupplied by the auxiliary power conversion block is terminated by acontroller that monitors the output current from the main powerconversion block). In an alternative implementation (e.g., at a loadlevel where the auxiliary power conversion block is efficient), one orboth of the auxiliary power conversion block contributes a share of thepower supplied to the variable electrical load. For example, in one ormore implementations, each auxiliary power conversion block will reachits substantially maximum load capacity before the “next” powerconversion block begins to supply power, wherein “next” refers to thepower conversion block with the next lower predesignated open circuitvoltage setting. Other implementations may be employed wherein reachingthe substantially maximum load capacity is not a prerequisite to turningon another power conversion block.

FIG. 7 illustrates example operations 700 for dynamic loading for aswitching power supply unit (PSU). The example operations 700 providepower from an electrical power input to a common output node. Aconversion operation 702 convert the electrical power input to outputpower supplied to the common output node using a first power conversionblock and a second power conversion block. The first power conversionblock is configured to supply a first power supply share to the commonoutput node and to decrease output voltage from the first powerconversion block while output current from the first power conversionblock reaches a rated current level. The second power conversion blockis configured with a predesignated open circuit voltage setting and isfurther configured to supply a second power supply share to the commonoutput node and to contribute the second output power supply share tothe common output node while the output voltage at the common outputnode has decreased to the predesignated electrical voltage setting.

In one implementation, a controlling operation 704 terminates the outputpower supply share supplied to the common output node from one of thepower conversion blocks while the output voltage at the common outputnode is at the open circuit voltage setting of the other powerconversion block. If the PSU includes multiple auxiliary powerconversion blocks, then the controlling operation 704 can terminate theoutput power supply share supplied to the common output node from any ofthe power conversion blocks, even if the output voltage at the commonoutput node is at the open circuit voltage setting of such powerconversion blocks.

FIG. 8 illustrates an example electronic device 800 (such as a computingdevice or a communications device) for implementing the features andoperations of the described technology. The electronic device 800 mayembody a remote control device or a physical controlled device and is anexample network-connected and/or network-capable device and may be aclient device, such as a laptop, mobile device, desktop, tablet; aserver/cloud device; an Internet-of-Things device; an electronicaccessory; or another electronic device. The electronic device 800includes one or more processor(s) 802 and a memory 804. The memory 804generally includes both volatile memory (e.g., RAM) and nonvolatilememory (e.g., flash memory). An operating system 810 resides in thememory 804 and is executed by the processor(s) 802.

In an example electronic device 800, as shown in FIG. 8 , one or moremodules or segments, such as applications 850, conversion blockcontroller software, firmware modules, are loaded into the operatingsystem 810 on the memory 804 and/or storage 820 and executed byprocessor(s) 802. The storage 820 may include one or more tangiblestorage media devices and may store predesignated open circuit voltagesettings, maximum rated currents, overload current levels, and otherdata and be local to the electronic device 800 or may be remote andcommunicatively connected to the electronic device 800.

The electronic device 800 includes a power supply 816, which is poweredby one or more batteries or other power sources and which provides powerto other components of the electronic device 800. The power supply 816may also be connected to an external power source that overrides orrecharges the built-in batteries or other power sources.

The electronic device 800 may include one or more communicationtransceivers 830, which may be connected to one or more antenna(s) 832to provide network connectivity (e.g., mobile phone network, Wi-Fi®,Bluetooth®) to one or more other servers and/or client devices (e.g.,mobile devices, desktop computers, or laptop computers). The electronicdevice 800 may further include a network adapter 836, which is a type ofcomputing device. The electronic device 800 may use the adapter and anyother types of computing devices for establishing connections over awide-area network (WAN) or local-area network (LAN). It should beappreciated that the network connections shown are exemplary and thatother computing devices and means for establishing a communications linkbetween the electronic device 800 and other devices may be used.

The electronic device 800 may include one or more input devices 834 suchthat a user may enter commands and information (e.g., a keyboard ormouse). These and other input devices may be coupled to the server byone or more interfaces 838, such as a serial port interface, parallelport, or universal serial bus (USB). The electronic device 800 mayfurther include a display 822, such as a touch screen display.

The electronic device 800 may include a variety of tangibleprocessor-readable storage media and intangible processor-readablecommunication signals. Tangible processor-readable storage can beembodied by any available media that can be accessed by the electronicdevice 800 and includes both volatile and nonvolatile storage media,removable and non-removable storage media. Tangible processor-readablestorage media excludes communications signals (e.g., signals per se) andincludes volatile and nonvolatile, removable and non-removable storagemedia implemented in any method or technology for storage of informationsuch as processor-readable instructions, data structures, programmodules, or other data. Tangible processor-readable storage mediaincludes, but is not limited to, RAM, ROM, EEPROM, flash memory or othermemory technology, CDROM, digital versatile disks (DVD) or other opticaldisk storage, magnetic cassettes, magnetic tape, magnetic disk storageor other magnetic storage devices, or any other tangible medium whichcan be used to store the desired information and which can be accessedby the electronic device 800. In contrast to tangible processor-readablestorage media, intangible processor-readable communication signals mayembody processor-readable instructions, data structures, programmodules, or other data resident in a modulated data signal, such as acarrier wave or other signal transport mechanism. The term “modulateddata signal” means a signal that has one or more of its characteristicsset or changed in such a manner as to encode information in the signal.By way of example, and not limitation, intangible communication signalsinclude signals traveling through wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, RF,infrared, and other wireless media.

Various software components described herein are executable by one ormore processors, which may include logic machines configured to executehardware or firmware instructions. For example, the processors may beconfigured to execute instructions that are part of one or moreapplications, services, programs, routines, libraries, objects,components, data structures, or other logical constructs. Suchinstructions may be implemented to perform a task, implement a datatype, transform the state of one or more components, achieve a technicaleffect, or otherwise arrive at a desired result.

Aspects of processors and storage may be integrated together into one ormore hardware logic components. Such hardware-logic components mayinclude field-programmable gate arrays (FPGAs), program- andapplication-specific integrated circuits (PASIC/ASICs), program- andapplication-specific standard products (PSSP/ASSPs), system-on-a-chip(SOC), and complex programmable logic devices (CPLDs), for example.

The terms “module,” “program,” and “engine” may be used to describe anaspect of a remote control device and/or a physical controlled deviceimplemented to perform a particular function. It will be understood thatdifferent modules, programs, and/or engines may be instantiated from thesame application, service, code block, object, library, routine, API,function, etc. Likewise, the same module, program, and/or engine may beinstantiated by different applications, services, code blocks, objects,routines, APIs, functions, etc. The terms “module,” “program,” and“engine” may encompass individual or groups of executable files, datafiles, libraries, drivers, scripts, database records, etc.

It will be appreciated that a “service,” as used herein, is anapplication program executable across one or multiple user sessions. Aservice may be available to one or more system components, programs,and/or other services. In some implementations, a service may run on oneor more server computing devices.

An example power supply unit for providing power from an electricalpower input to a common output node is provided. A first powerconversion block is electrically coupled to convert the electrical powerinput to a first output power supply share supplied to the common outputnode. The first power conversion block is configured to decrease outputvoltage from the first power conversion block based at least in part onoutput current from the first power conversion block reaching a ratedcurrent level. A second power conversion block is electrically coupledto convert the electrical power input to a second output power supplyshare supplied to the common output node. The second power conversionblock is configured with a predesignated open circuit voltage settingand is further configured to contribute the second output power supplyshare to the common output node based at least in part on the outputvoltage at the common output node decreasing to the predesignated opencircuit voltage setting.

Another example power supply unit of any preceding unit is provided,wherein the first power conversion block is configured with apredesignated open circuit voltage setting that is higher than thepredesignated open circuit voltage setting of the second powerconversion block.

Another example power supply unit of any preceding unit is provided,wherein the first power conversion block is configured to operate in aconstant current mode.

Another example power supply unit of any preceding unit is provided,wherein the second power conversion block is configured to operate in aconstant voltage mode.

Another example power supply unit of any preceding unit is provided,wherein the first power conversion block further includes a first powerconverter and a first feedback control circuit electrically coupled tothe first power converter and the common output node to monitor voltageat the common output node.

Another example power supply unit of any preceding unit is provided,further comprising a controller coupled to the first power converter andconfigured to terminate the first output power supply share supplied tothe common output node from the first power conversion block based atleast in part on the output voltage at the common output node beingabove a predesignated open circuit voltage setting of the second powerconversion block.

Another example power supply unit of any preceding unit is provided,wherein the second power conversion block further includes a secondpower converter and a second feedback control circuit electricallycoupled to the second power converter and the common output node tomonitor voltage at the common output node. The second feedback controlcircuit enables the second power conversion block to supply electricalpower to the common output node if the monitored voltage at the commonoutput node reaches the predesignated open circuit voltage setting ofthe second power conversion block.

Another example power supply unit of any preceding unit is provided,further comprising a controller coupled to the second power converterand configured to terminate the second output power supply sharesupplied to the common output node from the second power conversionblock based at least in part on the output voltage at the common outputnode reaching the predesignated open circuit voltage setting of thesecond power conversion block.

An example method of providing power from an electrical power input to acommon output node is provided. The example method includes converting,with a first power conversion block and a second power conversion block,the electrical power input to output power supplied to the common outputnode. The first power conversion block is configured to supply a firstoutput power supply share to the common output node and to decreaseoutput voltage from the first power conversion block based at least inpart on output current from the first power conversion block reaching arated current level. The second power conversion block is configuredwith a predesignated open circuit voltage setting and to contribute asecond output power supply share to the common output node based atleast in part on the output voltage at the common output node decreasingto the predesignated open circuit voltage setting.

Another example method of any preceding method is provided, furthercomprising terminating the first output power supply share supplied tothe common output node from the first power conversion block based atleast in part on the output voltage at the common output node beingabove the predesignated open circuit voltage setting of the second powerconversion block.

Another example method of any preceding method is provided, furthercomprising terminating the second output power supply share supplied tothe common output node from the second power conversion block based atleast in part on the output voltage at the common output node reachingthe predesignated open circuit voltage setting of the second powerconversion block.

Another example method of any preceding method is provided, wherein thefirst power conversion block is configured with a predesignated opencircuit voltage setting that is higher than the predesignated opencircuit voltage setting of the second power conversion block.

Another example method of any preceding method is provided, wherein thefirst power conversion block is configured to operate in a constantcurrent mode.

Another example method of any preceding method is provided, wherein thesecond power conversion block is configured to operate in a constantvoltage mode.

An example electrical device including a power supply unit for providingpower from an electrical power input to a common output node isprovided. The electrical device comprises a first power conversion blockelectrically coupled to convert the electrical power input to a firstoutput power supply share supplied to the common output node. The firstpower conversion block is configured to decrease output voltage from thefirst power conversion block based at least in part on output currentfrom the first power conversion block reaching a rated current level. Asecond power conversion block is electrically coupled to convert theelectrical power input to a second output power supply share supplied tothe common output node. The second power conversion block is configuredwith a predesignated open circuit voltage setting and is furtherconfigured to contribute the second output power supply share to thecommon output node based at least in part on the output voltage at thecommon output node decreasing to the predesignated open circuit voltagesetting.

Another example electrical device of any preceding device is provided,wherein the first power conversion block is configured to operate in aconstant current mode.

Another example electrical device of any preceding device is provided,wherein the first power conversion block further includes a first powerconverter and a first feedback control circuit electrically coupled tothe first power converter and the common output node to monitor voltageat the common output node.

Another example electrical device of any preceding device is provided,further comprising a controller coupled to the first power converter andconfigured to terminate the first output power supply share supplied tothe common output node from the first power conversion block based atleast in part on the output voltage at the common output node beingabove the predesignated open circuit voltage setting of the second powerconversion block.

Another example electrical device of any preceding device is provided,wherein the second power conversion block further includes a secondpower converter and a second feedback control circuit electricallycoupled to the second power converter and the common output node tomonitor voltage at the common output node, wherein the second feedbackcontrol circuit enables the second power conversion block to supplyelectrical power to the common output node if the monitored voltage atthe common output node reaches the predesignated open circuit voltagesetting of the second power conversion block.

Another example electrical device of any preceding device is provided,further comprising a controller coupled to the second power converterand configured to terminate the second output power supply sharesupplied to the common output node from the second power conversionblock based at least in part on the output voltage at the common outputnode reaching the predesignated open circuit voltage setting of thesecond power conversion block.

An example system for providing power from an electrical power input toa common output node is provided. The example system includes means forconverting, with a first power conversion block and a second powerconversion block, the electrical power input to output power supplied tothe common output node. The first power conversion block is configuredto supply a first output power supply share to the common output nodeand to decrease output voltage from the first power conversion blockbased at least in part on output current from the first power conversionblock reaching a rated current level. The second power conversion blockis configured with a predesignated open circuit voltage setting and tocontribute a second output power supply share to the common output nodebased at least in part on the output voltage at the common output nodedecreasing to the predesignated open circuit voltage setting.

Another example system of any preceding system is provided, furthercomprising means for terminating the first output power supply sharesupplied to the common output node from the first power conversion blockbased at least in part on the output voltage at the common output nodebeing above the predesignated open circuit voltage setting of the secondpower conversion block.

Another example system of any preceding system is provided, furthercomprising means for terminating the second output power supply sharesupplied to the common output node from the second power conversionblock based at least in part on the output voltage at the common outputnode reaching the predesignated open circuit voltage setting of thesecond power conversion block.

Another example system of any preceding method is provided, wherein thefirst power conversion block is configured with a predesignated opencircuit voltage setting that is higher than the predesignated opencircuit voltage setting of the second power conversion block.

Another example system of any preceding system is provided, wherein thefirst power conversion block is configured to operate in a constantcurrent mode.

Another example system of any preceding system is provided, wherein thesecond power conversion block is configured to operate in a constantvoltage mode.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular embodiments of a particular describedtechnology. Certain features that are described in this specification inthe context of separate embodiments can also be implemented incombination in a single embodiment. Conversely, various features thatare described in the context of a single embodiment can also beimplemented in multiple embodiments separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described program components and systems cangenerally be integrated together in a single software product orpackaged into multiple software products.

Thus, particular embodiments of the subject matter have been described.Other embodiments are within the scope of the following claims. In somecases, the actions recited in the claims can be performed in a differentorder and still achieve desirable results. In addition, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In certain implementations, multitasking and parallelprocessing may be advantageous.

A number of implementations of the described technology have beendescribed. Nevertheless, it will be understood that variousmodifications can be made without departing from the spirit and scope ofthe recited claims.

1. A power supply unit for providing power from an electrical powerinput to a common output node, comprising: a first power conversionblock electrically coupled to convert the electrical power input to afirst output power supply share supplied to the common output node, thefirst power conversion block being configured to decrease output voltagefrom the first power conversion block based at least in part on outputcurrent from the first power conversion block reaching a rated currentlevel; and a second power conversion block electrically coupled toconvert the electrical power input to a second output power supply sharesupplied to the common output node, the second power conversion blockbeing configured with a predesignated open circuit voltage setting andbeing further configured to contribute the second output power supplyshare to the common output node based at least in part on the outputvoltage at the common output node decreasing to the predesignated opencircuit voltage setting.
 2. The power supply unit of claim 1, whereinthe first power conversion block is configured with a predesignated opencircuit voltage setting that is higher than the predesignated opencircuit voltage setting of the second power conversion block.
 3. Thepower supply unit of claim 1, wherein the first power conversion blockis configured to operate in a constant current mode.
 4. The power supplyunit of claim 1, wherein the second power conversion block is configuredto operate in a constant voltage mode.
 5. The power supply unit of claim1, wherein the first power conversion block further includes a firstpower converter and a first feedback control circuit electricallycoupled to the first power converter and the common output node tomonitor voltage at the common output node.
 6. The power supply unit ofclaim 5, further comprising: a controller coupled to the first powerconverter and configured to terminate the first output power supplyshare supplied to the common output node from the first power conversionblock based at least in part on the output voltage at the common outputnode being above predesignated setting of the first power conversionblock.
 7. The power supply unit of claim 1, wherein the second powerconversion block further includes a second power converter and a secondfeedback control circuit electrically coupled to the second powerconverter and the common output node to monitor voltage at the commonoutput node, wherein the second feedback control circuit enables thesecond power conversion block to supply electrical power to the commonoutput node if the monitored voltage at the common output node reachesthe predesignated open circuit voltage setting of the second powerconversion block.
 8. The power supply unit of claim 7, furthercomprising: a controller coupled to the second power converter andconfigured to terminate the second output power supply share supplied tothe common output node from the second power conversion block based atleast in part on the output voltage at the common output node reachingthe predesignated open circuit voltage setting of the second powerconversion block.
 9. A method of providing power from an electricalpower input to a common output node, the method comprising: converting,with a first power conversion block and a second power conversion block,input power from the electrical power input to output power supplied tothe common output node, wherein the first power conversion block isconfigured to supply a first output power supply share to the commonoutput node and to decrease output voltage from the first powerconversion block based at least in part on output current from the firstpower conversion block reaching a rated current level, and the secondpower conversion block is configured with a predesignated open circuitvoltage setting and to contribute a second output power supply share tothe common output node based at least in part on the output voltage atthe common output node decreasing to the predesignated open circuitvoltage setting.
 10. The method of claim 9, further comprising:terminating the first output power supply share supplied to the commonoutput node from the first power conversion block based at least in parton the output voltage at the common output node being above thepredesignated open circuit voltage setting of the second powerconversion block.
 11. The method of claim 9, further comprising:terminating the second output power supply share supplied to the commonoutput node from the second power conversion block based at least inpart on the output voltage at the common output node reaching thepredesignated open circuit voltage setting of the second powerconversion block.
 12. The method of claim 9, wherein the first powerconversion block is configured with a predesignated open circuit voltagesetting that is higher than the predesignated open circuit voltagesetting of the second power conversion block.
 13. The method of claim 9,wherein the first power conversion block is configured to operate in aconstant current mode.
 14. The method of claim 9, wherein the secondpower conversion block is configured to operate in a constant voltagemode.
 15. An electrical device including a power supply unit forproviding power from an electrical power input to a common output node,the electrical device comprising: a first power conversion blockelectrically coupled to convert the electrical power input to a firstoutput power supply share supplied to the common output node, the firstpower conversion block being configured to decrease output voltage fromthe first power conversion block based at least in part on outputcurrent from the first power conversion block reaching a rated currentlevel; and a second power conversion block electrically coupled toconvert the electrical power input to a second output power supply sharesupplied to the common output node, the second power conversion blockbeing configured with a predesignated open circuit voltage setting andbeing further configured to contribute the second output power supplyshare to the common output node based at least in part on the outputvoltage at the common output node decreasing to the predesignated opencircuit voltage setting.
 16. The electrical device of claim 15, whereinthe first power conversion block is configured to operate in a constantcurrent mode.
 17. The electrical device of claim 15, wherein the firstpower conversion block further includes a first power converter and afirst feedback control circuit electrically coupled to the first powerconverter and the common output node to monitor voltage at the commonoutput node.
 18. The electrical device of claim 17, further comprising:a controller coupled to the first power converter and configured toterminate the first output power supply share supplied to the commonoutput node from the first power conversion block based at least in parton the output voltage at the common output node being above thepredesignated open circuit voltage setting of the second powerconversion block.
 19. The electrical device of claim 15, wherein thesecond power conversion block further includes a second power converterand a second feedback control circuit electrically coupled to the secondpower converter and the common output node to monitor voltage at thecommon output node, wherein the second feedback control circuit enablesthe second power conversion block to supply electrical power to thecommon output node if the monitored voltage at the common output nodereaches the predesignated open circuit voltage setting of the secondpower conversion block.
 20. The electrical device of claim 19, furthercomprising: a controller coupled to the second power converter andconfigured to terminate the second output power supply share supplied tothe common output node from the second power conversion block based atleast in part on the output voltage at the common output node reachingthe predesignated open circuit voltage setting of the second powerconversion block.